1918] 
C. 
Barber—Synoptic Keys to the Lygeide (Hemiptera) ao 
Head more or less distinctly exserted. Pronotum with a 
constricted ring-like collar. Body more or less elongate. 
D. Head strongly exserted, forming a short neck at base; the 
DD. 
postocular space about four times as long as the space 
between the antenna and eye. The eyes placed about 
midway on the head. Hind tibia provided with fine rigid 
bristles. Basal segment of posterior tarsus about as long 
as second and third together. Macropterous and brachy- 
FRROEOURS” TOR Sto rei re 2 Oa eae art Hereus Stal. 
Head much less exserted, commonly strongly contracted 
back of eyes; postocular space commonly subequal to or 
sometimes shorter than space between base of antenna 
and eye. 
E. Anterior lobe of pronotum, especially in brachypterous 
forms, globose, almost the diameter and about twice the 
length of posterior lobe. Postocular space subequal to 
space between antenna and eye. Scutellum much 
longer than wide. Head and pronotum shining. Hind 
tibia with rigid bristles. Posterior tarsus with first 
segment nearly three times as long as second and third 
together. Macropterous and brachypterous forms. 
Spherobius Uhl. 
EE. Anterior lobe of pronotum not so evidently globose and 
narrower than posterior lobe. Head and thorax seldom 
shining. Basal segment of posterior tarsus most com- 
monly not more than twice as long as second and third 
together, if three times as long as second and third then 
the posterior tibia is provided with long rigid bristles. 
F. Preocular space to base of antenna about three times 
as long as postocular space; head not strongly con- 
tracted back of eyes; apex of tylus not extended to 
middle of basal segment of antenna; this segment in- 
crassate and elongate, a little longer than basal segment 
of rostrum; second segment very elongate, over twice as 
long as the third or fourth, longer than third and fourth 
together. Pronotum with anterior lobe twice as long 
as posterior. Collar set off by a depressed series of 
punctures. The anterior femora armed with two rows 
of spines, the outer series confined to the subapex. 
